Thrust bearing comprising a spacing member

ABSTRACT

An axial bearing having at least one axial runner disk which has a radially extending portion and an axially extending annular flange. A plurality of rollers roll along the radially extending portion of the axial runner disk. A detachable spacing member of annular shape retained on the axial runner disk with the aid of fastening elements, forming a captive axial bearing arrangement. The annular spacing member has a plurality of spaced-apart projecting bosses arranged in the circumferential direction having an axial extent determined by predefined spacing between two connection parts. A second axial runner disk cooperates with the first disk and holds bearing rollers between them. The bearing may be employed in a hydrodynamic torque converter at the stator between the pump wheel and the turbine wheel of the converter.

FIELD OF APPLICATION OF THE INVENTION

The invention relates to an axial bearing having at least one axialrunner disk which has a radially extending portion and an axiallyextending annular rim, having a plurality of rollers which roll alongthe radially extending portion of the axial runner disk, and having adetachable spacing member which has an annular shape and is retained onthe axial runner disk with the aid of fastening elements, with theresult that a captive structural unit is formed.

BACKGROUND TO THE INVENTION

Axial bearings of this type with detachable spacing members are usedparticularly in vehicle transmissions in the automotive industry. Whensuch transmissions are assembled, such an axial bearing typically liesflat against a first transmission part. The associated other, second,transmission part is connected to the first transmission part by way ofthe axial bearing. The spacing member is selected after measurementshave been carried out during one of the transmission assemblyoperations, i.e. its correct axial thickness is determined according tothe dimensions to be observed for the spaced-apart transmission parts.

Such a generic axial bearing with a spacing member is already known fromDE 39 14 175 A1. It is produced from a plastic and has an annular shape.Another generic axial bearing is known from U.S. Pat. No. 4,733,979. Thespacing member is again annular and is connected to an axial runnerdisk. As is shown by FIG. 12 of this prior application, two parts whichcan be rotated relative to one another are connected to one another byway of this axial bearing, the required distance between the two partsbeing determined by the axial bearing and by the spacing disk fastenedthereto.

However, what happens in practice is that various differences alwaysoccur between the parts to be mounted, even in applications of the sametype. That in turn means that these production-dictated tolerances, forexample within a series of transmissions having the same dimensions, aredifferent in each individual case. In other words, this varying spacingwithin a transmission series from component to component cannot becompensated by the axial bearing alone. In each individual case, thecorresponding transmission has to be measured and the respective bearinghas to be provided, depending on the resulting measurement, with aselected spacing member, so that the required tolerance is observed.That in turn means that a large number of spacing members which differin their axial thickness must be kept available. According to the priorart, these spacing disks are produced from materials which all have adifferent initial thickness. It follows therefrom that, for toolingreasons alone, such a production of spacing members with differentthicknesses is highly expensive.

SUMMARY OF THE INVENTION

The object on which the invention is based is therefore to produce suchan assembled axial bearing arrangement in a more cost-effective manner.

According to the invention, this object is achieved according to thedefining part of claim 1, in conjunction with the preamble thereof, inthat the annular spacing member has projecting bosses which are spacedapart in the circumferential direction and whose axial extent isdetermined by the spacing to be observed between two connection partswhich are to be connected rotatably by means of the axial bearing.

The advantage of the spacing members according to the invention isparticularly that, by contrast with the prior art, they can be producedfrom a starting material of same thickness. It is thus possible usingsimple means to produce a number of spacing members for axial bearingswhich, while otherwise being of the same dimensions, have a differingaxial extent. The differing axial extent of the bosses is made possiblein a simple manner by means of a stamping ram which need only be alteredto a small degree. Only one tool is thus necessary for spacing membersof the same types but having differing axial extents.

A further essential advantage of the spacing members according to theinvention is that they do not have a planar contact face by virtue ofthe spaced-apart projecting bosses. In this way, the flow of oil throughsuch an axial bearing is significantly improved, something of crucialimportance in transmission construction if consumers connecteddownstream are to be supplied with a corresponding oil pressure.

Further advantageous embodiments of the invention are described insubclaims 2 to 7.

Provision is thus made as claimed in claim 2 for the bosses to becircular.

According to a further advantageous feature as claimed in claim 3, thespacing member is to be fabricated from a metallic material and thebosses are to be produced by a stamping operation.

A particularly advantageous design of the spacing member is described inclaim 4. Provision is made therein for this to have three retaining tabswhich are spaced apart in the circumferential direction, extend in theaxial direction and are provided with a retaining lug which extends inthe radial direction. This design ensures that the spacing member bearsexactly against the axial bearing.

It emerges from claim 5 that the retaining tabs are arranged on theouter or on the inner circumference of the annular spacing member. Thisdepends on whether the associated axial bearing is internally orexternally guided.

It emerges from a further feature of the invention as claimed in claim 6that the axially extending rim of the axial runner disk is provided witha plurality of segmentlike protrusions which are spaced apart uniformlyin the circumferential direction and extend in the radial direction, therim having a clearance between two segmentlike protrusions. This designensures that, on the one hand, the two components are prevented fromtwisting relative to one another and, on the other hand, that it ispossible to hold them firmly together to form a captive structural unit.

Finally, a specific application of the spacing member designed accordingto the invention emerges from claim 7. Provision is made therein forsuch an axial bearing with a fitted-on spacing member to be employed ina hydrodynamic torque converter, in which arrangement a casing whichrotates about an axis of rotation is connected to a pump wheel, aturbine wheel which can be rotated about the axis of rotation relativeto the pump wheel is arranged axially opposite said pump wheel, and astator which can be rotated relatively about the axis of rotation isarranged between the pump wheel and the turbine wheel and is supportedon the pump wheel and on the turbine wheel within the casing by means ofa respective axial bearing, the axial bearing situated between thestator and the pump wheel being provided with the annular spacingmember.

The invention will be explained in more detail by way of the exemplaryembodiments below.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 shows a perspective representation of a spacing member designedaccording to the invention,

FIG. 2 shows a perspective representation of the spacing member and ofan axial runner disk designed according to the invention,

FIG. 3 shows a perspective representation of this axial runner disk frombelow,

FIG. 4 shows an associated second axial runner disk with an insertedroller ring,

FIGS. 5 and 6 show a perspective representation of a complete axialbearing,

FIGS. 7 and 8 show a plan view of a complete axial bearing according tothe invention,

FIG. 9 shows a section through an axial bearing along the line IX-IX inFIG. 7,

FIG. 10 shows an enlarged representation of a detail in FIG. 9,

FIG. 11 shows a schematic representation of a torque converter accordingto the prior art,

FIG. 12 shows a longitudinal view through a stator of a torque converterwith an axial bearing arrangement according to the invention, and

FIGS. 13 and 14 show an enlarged representation of a detail according toFIG. 12.

DETAILED DESCRIPTION OF THE DRAWINGS

As can be seen from FIGS. 1 and 2, the spacing member 1 according to theinvention comprises the annular radial portion 2, which is provided witha plurality of bosses 2.1 spaced apart in the circumferential direction.In the present example, these bosses 2.1 are circular and are producedfrom the metallic spacing member by material displacement, for exampleby a stamping operation. The essential nature of the invention is that,while the spacing member 1 is otherwise completely identicallydimensioned, these bosses 2.1 have a differing axial extent. It ispossible to produce from the same starting material a number of spacingmembers 1 which differ only in the axial extent of the bosses 2.1, theaxial length of which is ultimately determined by the spacing betweenthe parts to be mounted. As can further be seen from the stated figures,the radially extending portion 2 of the spacing member 1 is providedwith retaining tabs 3 at three uniformly spaced-apart peripherallocations on its outer circumference and these retaining tabs extend inthe axial direction and each have a retaining lug 3.1 which points inthe radial direction. In the present case, this retaining lug 3.1 isdirected radially inwards, since the retaining tabs 3 are arranged onthe outer circumference of the radial portion 2. As can be seen fromFIG. 2, the spacing member 1 according to the invention does not have acontinuous planar contact face, the latter instead being formed by thesum of the axial bosses 2.1. It can be seen that a free space 2.2 isformed from boss 2.1 to boss 2.1 in the circumferential direction, thisclearance being of importance particularly in certain applications toallow oil to flow through such a bearing arrangement.

FIGS. 2 and 3 show an axial runner disk 4 onto which the spacing member1 designed according to the invention is snap-fastened. The axial runnerdisk 4 comprises the radially extending portion 5, which forms theraceway for rolling bodies, and the rim 6, which extends on the outercircumference in the axial direction. This outer rim 6 is provided witha plurality of segmentlike protrusions 6.1 which are spaced apart in thecircumferential direction and extend in the radial direction. In thepresent case, the axial runner disk 4 is provided with six suchprotrusions 6.1 of this type since the spacing member 1 has threeretaining tabs 3. The axially extending rim 6 of the axial runner diskis provided with clearances 6.2 which are spaced apart uniformly aroundthe circumference and which are in each case enclosed by a segmentlikeprotrusion 6.1 in the circumferential direction. These clearances 6.2promote the passage of oil through the bearing arrangement, actingtherefore as oil grooves. Adjoining this clearance 6.2 in the rim 6 thelatter has radially inwardly directed retaining lugs 6.3 which engage ina positively locking manner behind a rolling bearing cage (not shown).

It can also be discerned from FIG. 2 that the spacing member 1 can besimply clipped onto the axial runner disk 4 in the direction of thearrow, since precentering is provided by the spaced-apart, segmentlikeprotrusions 6.1. The spacing member 1 is made to bear with its retainingtabs 3 in such a way that the latter engage in the free space betweenthe two spaced-apart, segmentlike protrusions 6.1. It is ensured in thisway that mutual twisting of the axial runner disk 4 and the spacingmember 1 relative to one another is possible to only a very limiteddegree. This can only take place until the retaining tabs 3 of thespacing member 1 bear against the segmentlike protrusions 6.1 of theaxial runner disk 4. It can additionally be seen from FIG. 2 that, as aresult of the threefold arrangement of the retaining tabs 3 on thespacing member 1, the latter can be fitted onto the axial runner disk 4in a simple manner by springing into place. When the retaining lugs 3.1of the retaining tabs 3 engage in the clearance 6.2 in the outer rim 6,the axial runner disk 4 and the spacing member 1 are held togethercaptively.

FIG. 4 shows a second axial runner disk 7, the radial portion 8 of whichis not visible and constitutes the raceway for the roller ring 10, whichis formed by a cage 10.1 and rollers 10.2 accommodated therein. Bycontrast with the other axial runner disk 4, the second axial runnerdisk 7 has on its inner circumference a rim 9 which extends in the axialdirection and which is provided with clearances 9.1 which are uniformlyspaced apart in the circumferential direction. Arranged in theseclearances 9.1 are curved twist-preventing means 9.2 which engage inassociated cutouts of a connecting construction (not shown). Theseclearances also act as oil grooves and promote the passage of lubricantthrough the bearing. In addition, the inner rim 9 is provided with aplurality of retaining lugs 9.3 which point radially outward and engagebehind the cage 10.1 of the roller ring 10, with the result that the twocomponents are held one against the other.

FIGS. 5 and 6 illustratively represent an axial bearing arrangementwhich is designed according to the invention and which is composed ofthe first run-on disk 4 and of the second run-on disk 7, between whichdisks the roller ring 10 is arranged. Whereas the axial runner disk 4 isequipped with the rim 6 on its outer circumference, the second axialrunner disk 7 has this rim 9 on its inner circumference. In this way aself-contained, captive bearing arrangement is formed.

Finally, FIGS. 7, 8, 9 and 10 show the complete axial bearing structuralunit in different views or sectional representations. In the text whichfollows, reference is made particularly to the enlarged representationin FIG. 10. The complete axial bearing structural unit accordinglycomprises the roller ring 10, the rollers 10.2 of which are guided inthe cage 10.1. The bearing has the two axial runner disks 4 and 7, theaxial runner disk 4 being provided with the rim 6 on its outercircumference. In the case of the other runner disk 7, the rim 9 isarranged on the inner circumference. The radial portions 5, 8 of the tworunner disks 4, 7 form the associated raceways for the rollers 10.2.

As can further be seen, the rim 9 has its retaining lug 9.3, which isdirected radially outward, engaging around the cage 10.2. The spacingmember 1 is placed by way of its radial portion 2 on the runner disk 4or the radial portion 5 thereof and engages by way of the retaining lugs3.1 of the retaining tabs 3 in the clearance 6.2 in the outer rim 6 ofthe axial runner disk 4. As the drawing further shows, bosses 2.1project in the axial direction from the radial portion 2 of the spacingmember 1. These bosses have an axial extent 1 which may assume adifferent value depending on the predefined installation conditions.

An already known torque converter as shown in FIG. 11 is arranged in atransmission casing and includes the pump wheel 11, opposite this theturbine wheel 12, and the stator 13, which is situated between the pumpwheel 11 and the turbine wheel 12. Axial bearings 14, 15 are present atboth ends of the stator 13. The axial bearing 14 is used to support therotatable pump wheel 11, while the other axial bearing 15 is used tosupport the rotatable turbine wheel 12. The pump wheel 11 is in directconnection with a crankshaft of the internal combustion engine, whilethe turbine wheel 12 is coupled to a transmission input shaft. Thestator 13 is connected to the transmission casing via a free wheel 16.As a result of the centrifugal force, the pump wheel 11 conveys the oiloutward to the turbine wheel 12 by means of the pump wheel blades anddrives said turbine wheel. The blades of the turbine wheel 12 deflectthe oil onto the blades of the stator 13, which in turn feeds the oil tothe pump wheel 11. The pump wheel, turbine wheel and stator 11, 12, 13rotate about their common axis of rotation 17.

An exact and detailed description of the structure and the mode ofoperation of a hydrodynamic torque converter can be omitted at thispoint because it is sufficiently familiar to a person skilled in theart. Detailed information on hydrodynamic torque converters can befound, for example, in the technical book Viehweg, HandbuchKraftfahrtzeugtechnik [Motor vehicle engineering manual], FriedrichViehweg & Sohn Verlagsgesellschaft mbH Braunschweig or in the priorpublications DE 35 43 013 A1, DE 36 06 707 C2, DE 37 12 659 A1, DE 41 34369 A1 and DE 199 46 333 A1.

In this connection, it is also known to a person skilled in the art thathydrodynamic torque converters have a tendency to “swell”. What is meantby this is that the converter may be deformed in the axial directionowing to the high oil pressure. This swelling is taken into account inthe construction of the converter such that spacing dimensions in theaxial direction to be determined by measurement will be observed betweenthe stator 13 and pump wheel 11 on the one hand and between the stator13 and turbine wheel 12 on the other hand. This is done by employing aspacing disk in the case of the bearing 14 arranged on the right-handside, this spacing disk not being connected to the bearing 14, however.This spacing disk (not shown) is arranged between the stator 13 and theleft-hand axial runner disk of the axial bearing 14. The disadvantage ofthis is that the guide surface for the axial bearing 14 is lost becauseof this spacing disk. What may happen in an extreme case is that thebearing will fall from its seat in the case of the converter expandingsubstantially. During contraction, serious problems with respect to thefallen bearing may arise, possibly leading to premature failure of theconverter.

FIG. 12 and the enlarged representation in FIG. 13 show longitudinalsections of the stator 13 which is provided with the axial bearingarrangement according to the invention. As can be seen particularly fromFIG. 13, the stator 13 is provided with a shoulder 13.1 in at least partof which is made a groove 13.2. In a representation which is not shown,the rim 9 of the axial runner disk 7 is provided with a projection whichengages in the groove 13.2, so that the entire bearing arrangement isnot able to slide off the stator 13 in the axial direction. As canfurther be seen, the axial width, denoted by b, of the shoulder 13.1 isone hundred percent available as a guide surface for the axial runnerdisk 7, i.e. the associated rim 9 of the axial runner disk 7 has itsentire axial width seated on the shoulder 13.1 of the stator 13. Theassociated other axial runner disk 4 is provided with the spacing member1 in the manner already described, so that the radial portion 2 has itsbosses 2.1 extending in the axial direction of a converter cover asshown in FIG. 11.

According to the prior art, the spacing disk (not shown) would bearranged between the axial runner disk 7 and the contact face 13.3 ofthe stator 13. It can be deduced therefrom that the guide face b for anaxial bearing arranged there is reduced, i.e. said axial bearing wouldbe moved to the right. If this spacing disk (not shown) then had to beremoved, the entire axial bearing would have to be taken off the stator13.

By contrast, this is not required in the case of a bearing arrangementaccording to the invention, since the spacing member 1 is oriented inthe direction of the component to be supported. If it were then foundthat the spacing member 1 was used in an unsatisfactory width, i.e. withan incorrect axial extent of the bosses 2.1, all that is required is toremove the spacing member 1 and not the entire bearing arrangement as inthe case of the prior art. The axial bearing arrangement shown in FIG.13 is internally guided, i.e. the axial bearing has its inner diameterresting on the stator 13. In this case, the design then has to be suchthat the spacing member 1 is provided with the retaining tabs 3 on itsouter circumference.

Finally, FIG. 14 shows a stator 13 which bears an externally guidedaxial bearing. What is meant thereby is that this axial bearingarrangement has its axial runner disk 7 supported on an outer shoulder13.1. Consequently, the spacing member 1 is provided with retaining tabs3 on its inner circumference.

DESIGNATIONS

-   1.1 spacing member-   2 radial portion-   2.1 boss-   2.2 free space-   3 retaining tabs-   3.1 retaining lug-   4 axial runner disk-   5 radial portion-   6 rim-   6.1 segmentlike protrusion-   6.2 clearance-   6.3 retaining lug-   7 axial runner disk-   8 radial portion-   9 rim-   9.1 clearance-   9.2 twist-preventing means-   9.3 retaining lug-   10 roller ring-   10.1 cage-   10.2 roller-   11 pump wheel-   12 turbine wheel-   13 stator-   13.1 shoulder-   13.2 groove-   13.3 contact face-   14 axial bearing-   15 axial bearing-   16 free wheel-   17 axis of rotation-   b width-   1 axial extent

1. An axial bearing comprising: at least one axial runner disk includinga radially extending portion extending into an axially extending rim, aplurality of rollers which roll along the radially extending portion ofthe axial runner disk, a detachable annular spacing member retained onthe axial runner disk and fastening elements retaining the spacingmember on the axial runner disk for forming a captive structural unit,and projecting bosses on the annular spacing member, the bosses beingspaced apart in the circumferential direction and having a selectedaxial extent related to spacing between two connection parts which areto be rotatably connected by the axial bearing.
 2. The axial bearing asclaimed in claim 1, wherein the bosses are circular.
 3. The axialbearing as claimed in claim 1, wherein the spacing member is of ametallic material and the bosses are produced by a stamping operation.4. The axial bearing as claimed in claim 1, further comprising retainingtabs on the spacing member, the tabs are spaced apart in thecircumferential direction around the spacing member, extend in the axialdirection from the spacing member, and each tab has a retaining lugwhich extends in the radial direction.
 5. The axial bearing as claimedin claim 1, wherein the annular spacing member has an outer and an innercircumference and the retaining tabs are arranged on at least one of theouter and the inner circumference of the annular spacing member.
 6. Theaxial bearing as claimed in claim 1, further comprising a plurality ofsegmentlike protrustions on the axially extending rim of the axialrunner disk, the protrusions are spaced apart in the circumferentialdirection and each protrusion extends in the radial direction, the rimhaving a respective clearance between each two successive segmentlikeprotrusions.
 7. A hydrodynamic torque converter, comprising: a casingwhich is rotatable about a respective axis of rotation, a pump wheel towhich the casing is connected; a turbine wheel which is rotatable aboutthe axis of rotation relative to the pump wheel and is arranged axiallyopposite the pump wheel; a stator which is rotatable relatively to theturbine wheel about the axis of rotation, and is arranged between thepump wheel and the turbine wheel; and the axial bearing as claimed inclaim 1 supporting the stator on the pump wheel and on the turbine wheeland within the casing, wherein the axial bearing is situated between thestator and the pump wheel and the annular spacing member is on thebearing.
 8. The axial bearing as claimed in claim 4, wherein there arethree of the retaining tabs circumferentially spaced apart.
 9. The axialbearing as claimed in claim 1, further comprising: a second annularrunner disk, with the at least one and the second disks positioned onrespective axially opposite sides of the rollers and defining races forthe rollers; the second disk also having an axially extending rim, andthe rims being placed for radially retaining the rollers between thecircular disks and the races thereof; the spring member being axiallyoutward of the at least one disk away from the second disk, and thebosses extending axially outward from the at least one disk.
 10. Theaxial bearing as claimed in claim 1, wherein the axially extending rimis circular.